Fix build problem on 32-bit linux.
Fix build problem on 32-bit linux.

Our use of numpy's get_info probably still needs some fine-tuning.
alexis-roche/nireg,alexis-roche/niseg,alexis-roche/register,bthirion/nipy,arokem/nipy,arokem/nipy,alexis-roche/register,alexis-roche/nireg,bthirion/nipy,bthirion/nipy,alexis-roche/niseg,nipy/nireg,arokem/nipy,alexis-roche/nipy,alexis-roche/nipy,nipy/nipy-labs,nipy/nireg,alexis-roche/nipy,nipy/nipy-labs,bthirion/nipy,alexis-roche/nipy,alexis-roche/register,arokem/nipy